ML20128B742
| ML20128B742 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 09/26/1992 |
| From: | GENERAL PUBLIC UTILITIES CORP. |
| To: | |
| Shared Package | |
| ML20128B732 | List: |
| References | |
| TR-008, TR-008-R00, TR-8, TR-8-R, NUDOCS 9212040072 | |
| Download: ML20128B742 (5) | |
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OYSTER CREEK NUCLEAR GENERATING STATION STRUCTURAL EVALUATION OF THE SPENT FUEL POOL TOPICAL REPORT 088 REV. O r
O Project Not B/A 402880 Authors: Ma tha Gott d
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I TR 088-I Rev..0 Page 2 of 5
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JOi ABSTRACT A structural evaluation c: the Spent Fuel Pool (SFP) at the Oyster. Creek Nuclear -
Generating Station (OCNGS) was performed by ABB Impell Co. in order to evaluate the SFP concrete structure for consolidated-and unconsolidated fuel loads in-addition to other design basis loads (i.e.
dead -loads,- live loads, thermal i
gradients, seismic loads and cask drop accident).
This analysis was performed in order to:
1.
evaluate the istpact of providing additional storage in the SFP using fuel-rod consolidation, 2.
determine the effects of the existing concrete cracks in the SFP alab and supporting structures, 3.
determine the ef fects of the reduced ombedment of the bottom SFP slab rebars into the supporting beams and walls.
A detailed finite element model of the SFP concrete structure with connecting and supporting members was generated for this analysis as described in detail in the ABB Impell Co. Report No. 03-0310-1341 Rev. O._
This model is..' o f -
-attached sufficient size and detail to predict cracking and to account for internal redistribution of forces. Thus, the model encompasses the nocthern half of the.
Reactor Building and includes all structural-elements betwesn elevation 23' and-elevation 119'.
The model includes sufficient detail to permit simulation of observed conditions including known cracks and as-built reinforcing details.
The results of the analysis described in the attached ABB Impell Co. report O
demonstrate that the OCNGS SFP meets the requirements of ACI349-80 for all load combinations in the OCNGS updated FSAR section 9.1.2.3.
The general pattern of cracks observed in the SFP and connected structures - as well as specific-individual cracks are predicted by.-the analysis. The analysis demonstrates that the cracks do not jeopardize the structural integrity of the SFP or its connected structures.
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. i TR'088
-l Rev. 0 Page-3 of 5 TABLE OF CONTENTS-Paoe
1.0 INTRODUCTION
4 2.0 HKIKQpa.-..........
4-3.0 RESULTS 5
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4.0 CONCLUSION
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-I 5.0 BRERENCJLS 5
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.'TR 088
-Rev. 0 Page 4 of 5
1.0 INTRODUCTION
The attached ABB Impell Co, Report No. 03-0370-1341, Rev. O, " oyster Creek Nuclear Generating Station Structural Evaluation of the Spent Fuel 1 Pool" describes in detail the analyses performed to demonstrate the structural integrity of the SFP.
2.0 tLETHODS 2.1 An Analysis criteria Document was developed which defines the general technical requirement as well as the detailed directions for their implementation.
The Analysis Criteria Document is-incorporated in the attached ABB Impell Co. Report as Appendix-B, 2.2 A detailed finite element model of the SFP concrete structure with connecting and s"pporting members was generated using the ANSYS computer program in order to consider all required loads, load combinations and specific features of the SFP.
The model is described in Section 2 et the Report.
2.3 The analysis considers the effects of dead loads, live loads, thermal gradients, seismic loads and cask drop accident using FSAR loads and load combinations.
The evaluation of section capacities and stresses was performed in accordance with ACI349.-
2.4 The specific features of the SFP and its supporting structures considered in the analysis are:
1.
the reduced embedment length of bottom reinforcing bars connecting the SFP slab to supporting beams / walls, O_
2.
the integral connection of the floor slabs and drywell shield wall with the SFP structure, 3.
cracks on the concrete girder r.pporting the SFP (column line RE) and the bottom of the floor slab beneath_the SFP north wall, as well as cracks on areas of the dcywell shield wall connection to the SFP.
2.5 Analysis Cases A, B, C and D were considered during the analysis as
]isted below and as described in'Section 3.2 of the Report.
Case As Baseline analysis, normal plant operating loads with rack and fuel loads in place in 1983, - theresl conditions (winter) that favored c7ncrete cracking; no seismic and cask drop loads and only existing equipment live loads.
Case B Same loads as Case A in addition to reduced embedment of the bottom slab rebar into'the supporting structures.
Case C:
Licensed condition. Normal plant operating loads and the -
fully loaded high density racks presently in place, summer and winter thermal gradients, design live loads,' seismic-loads'and cask drop load.
Reduced embedment'rebar and existing cracks were considered.
Case D Same loads and conditions as Case C-except that consolidated fuel assemblies were assumed-in the SFP.
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Analysis Cases A and E were specifically developed to provide an-understanding of the behavior of che pool under sustained mechanical.
loads and thermal cradients. During the course of the aaalysis, it was determined that the behavior of-the pool and the. formation iof crsexs could be simulated using. Case C and that the results of Case C enveloped those of cases A and B.
Therefore, analysis Casem A and B were not finalized. Analysis case D was completed to evaluate the effects of storing additional fuel to the spent fuel pool. using consolidated fuel assemblies. The report therefore focuses on the results of analysis cases C and D.
2.6 The behavior of the SFP structare is described in Section 4 of the Report.
3.0 RESULTS 3.1 The evaluation process and a summary of results are described in Section 5 of the Reporc.
3.2 The results of the analyses described in the Report ; demonstrate that the OCNGS SFP meeta the requirements of ACI349-80 for all applicable load combinitions. -The general pattern of cracks observed in the SFP and connected structures, as well as specific -individual cracks are predicted by this analysis.
3.3 Although the SFP structure can support consolidated fuel loads, this:
4 loading is not recommended due to the lack of any margin in one of the spent fuel pool supporting elements under consolidated fuel loads.
4.0 CONCLUSION
ji 4.1 Conclusions are presented in Section 5.4 of the Report.
4.2 The structure is in full comp.liance with ACI349-80 for all loads for which the plant was licensed, f
5.0 REFERENCES
5.1 ABB Impell - Report No. 03-0370-1341, OCNGS Structural Evaluation of the Spent Fuel Pool, Rev. O, 6/29/92 Attachment to this TR.
Code Requirements. for Nuclear Safety Related Concrete"
-5.2 ACI349 Structures, 1980.
5.3 OCNGS FSAR Update, Section.9.1.2.3.
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